Development of a non-rodent model using light-activated channel technology to cur

描述(申请人提供)：导致光感受器丧失的退行性疾病，包括老年性黄斑变性(AMD)和视网膜色素变性(RP)，在发达国家是常见的失明原因。这些疾病在很大程度上避免了连接视网膜和大脑中心靶点的视网膜神经节细胞的连接和功能。因此，使视网膜神经节细胞直接对光做出反应的策略在开发这些疾病的治疗方法方面具有很大的前景。感光神经节细胞将绕过受损的光感受器，但利用视网膜以外的正常视觉通路。其他实验室此前已经证明，在视网膜细胞中可以表达光激活的阳离子通道-视紫红质-2(ChR2)。研究表明，在光感受器退化的啮齿动物模型中，ChR2的表达可以使视网膜细胞变得光敏。由于视网膜中ChR2的表达，光反应被传递到视皮层，并可能构成基本的视觉行为。然而，在临床上考虑使用ChR2或类似的光激活分子来治疗视网膜退行性疾病之前，还有大量的工作要做。这项R21提案解决了两个需要解决的重要问题。具体目的1将确定在非啮齿动物模型系统中如何在视网膜神经节细胞中获得广泛、稳定的ChR2表达，以及这种表达是否会导致视网膜神经节细胞的视觉反应，这些细胞被传递到外侧膝状体和初级视皮层细胞。具体目的2将确定由视网膜神经节细胞中ChR2的表达所引起的视觉是否能够增强或干扰正常视觉通路的发育和成人功能。这两个目标的成功完成将使该领域大大接近能够将光激活通道技术转化为临床的目标，并将提供申请资金所需的初步数据，以确定这种方法是否可以用于在视网膜脱离失明模型中产生行为有用的视觉。 公共卫生相关性：这项研究的长期目标是开发治疗由于光感受器功能丧失而导致的各种形式的失明，包括年龄相关性黄斑变性和视网膜色素变性。实验将测试通过表达光激活离子通道来人工使视网膜细胞变得敏感是否是治疗这些疾病的一种有前途的方法。

DESCRIPTION (provided by applicant): Degenerative diseases that result in the loss of photoreceptors, including Age-related Macular Degeneration (AMD) and Retinitis Pigmentosa (RP), are common causes of blindness in the developed world. These diseases largely spare the connections and functions of the retinal ganglion cells that link the retina to central targets in the brain. Therefore, the strategy of rendering retinal ganglion cells directly responsive to light holds a great deal of promise for developing therapies for these diseases. Light-sensitive ganglion cells would bypass the damaged photoreceptors, but take advantage of the normal visual pathways beyond the retina. Other laboratories have previously demonstrated that it is possible to express the light-activated cation channel, channelrhodopsin-2 (ChR2), in retinal cells. Studies have shown that in a rodent model of photoreceptor degeneration, expression of ChR2 can render retinal cells photosensitive. Light responses due to the expression of ChR2 in the retina are transmitted to the visual cortex, and can underlie rudimentary visual behaviors. A great deal of work remains to be done, however, before the use of ChR2 or similar light- activated molecules to treat retinal degenerative diseases could be contemplated in a clinical setting. This R21 proposal addresses two important issues that need to be tackled. Specific aim 1 will determine how best to obtain widespread, stable expression of ChR2 in retinal ganglion cells in a non- rodent model system, and whether such expression leads to visual responses in retinal ganglion cells that are transmitted to lateral geniculate nucleus and primary visual cortex cells. Specific aim 2 will determine whether the vision caused by the expression of ChR2 in retinal ganglion cells can either enhance or interfere with the development and adult function of normal visual pathways. Successful completion of these two aims will bring the field significantly closer to the goal of being able to translate light-activated channel technology into the clinic, and will provide preliminary data needed to apply for funding to determine whether this approach can be used to produce behaviorally useful vision in a retinal detachment model of blindness. PUBLIC HEALTH RELEVANCE: The long-term goal of this research is to develop methods to cure forms of blindness caused by the loss of photoreceptor function including Age-related Macular Degeneration and Retinitis Pigmentosa. Experiments will test whether artificially making retinal cells photosensitive through expression of light- activated ion channels is a promising approach to curing these diseases.